SM 25x275 [2xM8] / N42 - magnetic separator

Advantages and disadvantages of neodymium magnets.

Besides their stability, neodymium magnets are valued for these benefits:

• They have constant strength, and over more than ten years their attraction force decreases symbolically – ~1% (in testing),
• They possess excellent resistance to weakening of magnetic properties due to external magnetic sources,
• Thanks to the smooth finish, the surface of nickel, gold-plated, or silver gives an elegant appearance,
• The surface of neodymium magnets generates a strong magnetic field – this is a distinguishing feature,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, enabling action at temperatures approaching 230°C and above...
• In view of the ability of free molding and customization to specialized needs, NdFeB magnets can be produced in a broad palette of forms and dimensions, which increases their versatility,
• Fundamental importance in modern technologies – they are commonly used in hard drives, motor assemblies, medical devices, also multitasking production systems.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• They are fragile upon heavy impacts. To avoid cracks, it is worth securing magnets using a steel holder. Such protection not only shields the magnet but also improves its resistance to damage
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• Due to limitations in creating threads and complicated shapes in magnets, we recommend using cover - magnetic mount.
• Health risk related to microscopic parts of magnets pose a threat, in case of ingestion, which becomes key in the aspect of protecting the youngest. Furthermore, small components of these magnets can be problematic in diagnostics medical in case of swallowing.
• Due to complex production process, their price is relatively high,

Maximum lifting force for a neodymium magnet – what it depends on?

The specified lifting capacity represents the peak performance, recorded under optimal environment, specifically:

• on a block made of mild steel, effectively closing the magnetic flux
• whose transverse dimension reaches at least 10 mm
• characterized by even structure
• under conditions of gap-free contact (surface-to-surface)
• under axial application of breakaway force (90-degree angle)
• at conditions approx. 20°C

What influences lifting capacity in practice

During everyday use, the actual holding force is determined by a number of factors, ranked from crucial:

• Space between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by varnish or dirt) drastically reduces the pulling force, often by half at just 0.5 mm.
• Direction of force – highest force is reached only during pulling at a 90° angle. The force required to slide of the magnet along the plate is typically many times smaller (approx. 1/5 of the lifting capacity).
• Steel thickness – too thin sheet does not close the flux, causing part of the flux to be escaped into the air.
• Plate material – mild steel gives the best results. Alloy steels lower magnetic permeability and holding force.
• Plate texture – smooth surfaces guarantee perfect abutment, which improves force. Uneven metal weaken the grip.
• Thermal conditions – neodymium magnets have a sensitivity to temperature. When it is hot they are weaker, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity was determined with the use of a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular detachment force, however under shearing force the holding force is lower. Moreover, even a small distance {between} the magnet’s surface and the plate decreases the load capacity.